The aforementioned copending application Ser. No. 10/368,909 describes a torque wrench which includes selector mechanism for manually selecting any of a number of different preset torque values, and for latching the selector mechanism in the selected value position, so that the selector mechanism cannot accidentally be moved during use of the wrench, thereby inadvertently changing the preset torque value. The selector mechanism includes a locking structure which fits inside the tubular lever arm of the wrench and has a plurality of circumferentially spaced holes or keyways, respectively corresponding to preset torque levels, and into which a key on a rotatable member may be inserted. A stop on the rotatable member is engageable with a portion of the locking structure to limit rotation. While this arrangement generally works satisfactorily, it has experienced a number of disadvantages in use.
The arrangement of the key and stop on the rotatable member are such that rotation is limited to approximately 180°, thereby necessarily limiting the number of preset positions that can be utilized. Further limiting the number of available positions is the fact that the diameter of the locking structure is limited by the inside diameter of the tubular lever arm. This limited available diameter also limits the size of the holes or keyways and, correspondingly the size of the key which fits therein. Accordingly, breakage of the key in use may result.